Formic acid (FA) is a promising hydrogen storage carrier for high power density hydrogen fuel cells. However, dehydrogenation of FA usually produces CO by-products that poison the catalyst. The prevention of FA decomposition into CO within high-temperature proton exchange membrane (HT-PEM) systems operating at 130–200 °C remains a formidable scientific challenge. Here, we propose a Ni doping-induced active phase transition of molybdenum carbide on carbon-based catalysts, enhancing hydrogen production from FA. Ni-MoC/NC achieves complete FA conversion at 190 °C, maintaining stable catalytic performance over 170 h. In MoC/NC, Mo primarily exists as β-Mo₂C and γ-Mo₂N, while in Ni-MoC/NC, it predominantly forms α-MoC and γ-Mo₂N. XRD and XPS analyses reveal that Ni doping induces the transformation of β-Mo₂C into α-MoC, improving catalytic performance. Mechanistic studies identify HCOO* as a key intermediate in FA dehydrogenation on Ni-MoC/NC. The catalyst promotes the dissociation of HCOOH* into HCOO*, reduces the energy barrier for HCOO* conversion to CO₂*, and inhibits CO by-product formation, accelerating FA dehydrogenation. These findings highlight Ni-MoC/NC as a robust catalyst for efficient hydrogen production.

CO₂-assisted steam gasification of rice straw (RS) offers a promising approach for both the sustainable utilization of rice straw and the reduction of CO₂ emissions. This study investigates the transformation of RS during pyrolysis and gasification in a fixed-bed reactor, with structural changes observed through solid-state13C nuclear magnetic resonance and Fourier-transform infrared (FT-IR) spectroscopy. The gas composition is analyzed by gas GC, and covalent bonds are quantified through carbon structure and elemental analysis. The results demonstrate that steam acts as a key reactant in the gasification process, significantly enhancing the pyrolysis of RS and leading to higher hydrogen yields. CO₂ serves as an oxidant above 500 ◦C, oxygenating aromatic rings and initiating ring-opening reactions to form active C(O) intermediates that are crucial for hydrogen production. The hydrogen yield increases similarly to H₂O gasification, while methane and carbon monoxide decrease significantly after gasification over 700 ◦C. The H₂/CO ratio improves from 0.64 in N₂ to 1.46 in H₂O, and further to 1.71 in CO₂-H₂O at 700 ◦C. CO₂-assisted steam gasification optimizes the reactive interface activity, promoting the selective formation of hydrogen and improving the efficiency of the gasification process. Furthermore, CO₂ plays a pivotal role in enhancing the formation of active C(O) intermediates, which further facilitates the production of high-purity hydrogen. The process also induces the formation of a regular micro-pore structure, improving the overall efficiency and selectivity of directional hydrogen generation.

Reactive oxygen species (ROS) play a central role in redox catalysis over spinel oxides, contributing to both thermal and electrochemical oxidation processes, especially in the removal of volatile organic compounds (VOCs). Species such as lattice oxygen (O_latt) and adsorbed oxygen (O_ads) govern catalytic performance through structure-dependent activation and regeneration pathways. This review critically evaluates three major strategies for tuning ROS behavior: surface defect engineering, lattice doping and interface construction. This study delves into the activation and migration mechanisms of diverse oxygen species at the surface and bulk phases of metal oxides from an electronic perspective. Using spinel oxides renowned for their complex and abundant surface-active oxygen species as research object, we systematically synthesized the molecular dynamics (MD) and density functional theory (DFT) calculations reported in existing literature to elucidate the intrinsic correlations between oxygen species and the reaction rates of the catalytic oxidation processes of various VOCs. Based on existing research, this work proposes rational design principles for spinel-based catalysts in oxidation reactions, aiming to advance the rational development of next-generation VOCs oxidation catalysts.

Selective phosphate recovery from digestate-derived effluents remains a technical bottleneck due to high background salinity and strong multi-anion competition. To address this, waste peanut shells were valorized into activated biochar and functionalized with goethite (α-FeOOH) to form a regenerable anode for membrane capacitive deionization (MCDI). When treating real anaerobic-digestion membrane-bioreactor (AD-MBR) permeate, the optimized 20 wt% α-FeOOH/BC anode achieved a phosphate enrichment factor of 11.46 ± 0.61 and selectivity factors ≥ 5.47 against major competing anions, producing a phosphate-rich concentrate of 695–790 mg/L. The process remained stable over 20 adsorption-desorption cycles, maintaining a desorption efficiency of 0.94 ± 0.03 and negligible Fe loss (0.59% of the initial Fe inventory). XPS analysis confirmed the mechanism involved reversible inner-sphere Fe–O–P complexation. The mean recovery-specific energy consumption was 9.07 ± 0.64 kWh/kg-P. Overall, this study establishes a sustainable waste-to-resource framework, demonstrating that α-FeOOH-functionalized biochar electrodes can effectively couple agricultural residue valorization with closed-loop phosphate recovery from complex digestate permeates.

Carnot batteries are investigated as a potential alternative to electro-chemical batteries for grid-scale electricity storage, which is a crucial element to the decarbonisation of energy systems via variable renewable energy sources. In this work, a comprehensive life cycle assessment of the construction and end-of-life phases of two Rankine-based Carnot battery system configurations is presented, comparing water and thermal oil as hot thermal energy storage fluid. Both are benchmarked against lithium-ion batteries as the most common electro-chemical battery alternative. To enhance the robustness of the analysis, uncertainties in the input parameters and life cycle inventory data are explicitly considered and analysed. The deterministic results show that the Carnot battery using water as hot storage fluid performs best in 13 of 18 environmental impact categories. For example, the climate change impact is up to 23% lower. Thermal energy storage systems are identified as the dominant contributors, accounting for more than 50% of the environmental impact across most impact categories. The stochastic results considering uncertainty show that the Carnot battery with water tends to have environmental impacts on par with lithium-ion batteries, while the Carnot battery with thermal oil tends to perform the worst.

A significant amount of pressure energy is wasted during natural gas pressure reduction, while the cold energy generated from expansion is utilized inefficiently and typically relies on fossil fuel combustion for reheating. To address these challenges, this study proposes a pressure energy recovery system designated Int-ORC that combines an Organic Rankine Cycle, photovoltaic power generation, and alkaline water electrolysis for hydrogen production. Based on actual operational data from a pressure reduction station in Inner Mongolia, China, a coupled thermodynamic and economic model was developed using MATLAB to evaluate system performance. The Int-ORC system is compared against a basic pressure energy recovery system designated Ref. A and a pressure energy recovery system with hydrogen production designated Ref. B. The results show that the Int-ORC system achieves primary energy saving rates of 3.81 in summer and 2.98 in winter, representing improvements of 0.14 and 0.81 over Ref. A and Ref. B, respectively. The cold energy is fully utilized, achieving zero fossil fuel consumption. Hydrogen production rates reach 18.41 m3/h in summer and 18.78 m3/h in winter, both outperforming Ref. B. This study provides a technical foundation for the construction of next-generation gas stations integrating power generation, hydrogen production, and hydrogen blending functionalities.

The continuous advancement of urbanization is usually accompanied by a steady increase in urban energy consumption. A complex multi-factor influence network is embedded behind this positive correlation. By taking Jinan as the research object, a system dynamics model is constructed, which considers economy, energy, environment and other factors related to the urban power system (UPS). With electricity supply and demand as the clue, the key factors affecting carbon emissions of the UPS are traced. Low-carbon development path for the UPS is also designed. 4 key factors are identified, and they are categorized into 3 regulatory factors: industrial structure, energy storage technology, energy consumption intensity. They are used to design development scenario. In the suitable scenario combination, the GDP of the tertiary sector grows by 7% annually, energy storage equipment prices drop by 7% annually, the electricity consumption per GDP in the secondary sector drop by 3.3% annually. The average carbon emission intensity of the UPS can be reduced to 251.52 kgCO₂/104 CNY during 2021-2025. The final suggestion for the UPS low-carbon development path is put forward: “industrial structure→energy consumption intensity→energy storage technology”. These conclusions can provide scientific guidance for the low-carbon development of the UPS.

To address the demand for low-carbon binders with high early-age strength for gold tailings cementation, a sulfur-aluminum-ferric gold tailings cementitious material (SGCM) was developed using low-carbon sulfur-aluminum-ferric cementitious material (LSCM), gypsum, lime, and ordinary Portland cement (OPC). The binder composition was optimized through ternary and quaternary system experiments, and the corresponding hydration mechanism was investigated by isothermal calorimetry, X-ray diffraction, thermogravimetric analysis and scanning electron microscopy. The optimal proportion was identified as an LSCM:(gypsum + lime):OPC mass ratio of 1:1.2:0.4. At a cement-to-sand ratio of 1:4 and a filling concentration of 71%, the optimized SGCM achieved compressive strengths of 3.40 MPa at 3 d and 8.26 MPa at 28 d, showing superior early-age strength and competitive long-term strength compared with representative cementitious systems reported in previous studies. In addition, when applied at a reduced cement-to-sand ratio of 1:6, SGCM maintained compressive strength comparable to that of the OPC system at 1:4, while reducing the carbon emission factor by 70.2%; under the self-produced LSCM scenario, the material cost was further reduced by 15.0%. Mechanistic analyses revealed that increasing gypsum and lime contents promoted AFt formation but also transformed AFt into shorter and thicker crystals, whereas OPC incorporation enhanced early hydration, increased C-S-H generation, and densified the microstructure. AFt provided skeletal support, while C-S-H provided filling and bonding, and their synergy governed the strength development of SGCM.